All semiconductors, whether by design or accident, contain point defects that strongly influence their electronic, optical, and thermal properties. Our current research interests include defect identification via scanning tunneling spectroscopy, elucidating the physics and chemistry of point defects on thermal transport in semiconductors and identifying the limits of doping in wide band gap semiconductors.  We use a combination of first-principles calculations based on density functional theory with complementary semi-empirical methods.  Materials of interest include wide-band gap semiconductors (group III-nitrides, group III-oxides, diamond) and two-dimensional materials with potential applications in quantum information processing, single-photon sources, optoelectronic devices, and power electronics. The postdoc will have the opportunity to closely collaborate with experimental groups and will have access to state-of-the-art computational resources.

References

“Direct evidence for carbon incorporation on the nitrogen site in AlN”, D. Wickramaratne, M. Siford, Md. S. Mollik, J.L. Lyons, and M. E. Zvanut, Phys. Rev. Materials 8, 094602 (2024)

“Donor doping of corundum (AlxGa1−x)2O3”, D. Wickramaratne, J.B. Varley, and J.L. Lyons, Appl. Phys. Lett. 121, 042110 (2022)

"Defect identification based on first-principles calculations for deep level transient spectroscopy", D. Wickramaratne, C.E. Dreyer, B. Monserrat, J-X. Shen, J.L. Lyons, A. Alkauskas and C.G. Van de Walle, Appl. Phys. Lett. 113, 192106 (2018)

"Nontrivial doping evolution of electronic properties in Ising-superconducting alloys", W. Wan, D. Wickramaratne, P. Dreher, R. Harsh, I.I. Mazin, and M.M. Ugeda, Adv. Mater., 34, 26, (2022)

“The deep-acceptor nature of the chalcogen vacancies in 2D transition-metal dichalcogenides”, S. Khalid, B. Medasani, J.L. Lyons, D. Wickramaratne, and A. Janotti, 2D Mater. 11 021001 (2024)

defects; density functional theory; semiconductors; tunneling; thermal conductivity; two dimensional materials; wide-band gap semiconductors

citizenship

Open to U.S. citizens and permanent residents

level

Open to Postdoctoral applicants

Additional Benefits

relocation

Awardees who reside more than 50 miles from their host laboratory and remain on tenure for at least six months are eligible for paid relocation to within the vicinity of their host laboratory.

health insurance

A group health insurance program is available to awardees and their qualifying dependents in the United States.